Physicians make widespread use of catheters today in medical procedures to gain access into interior regions of the body. It is important that the physician can control carefully and precisely the movement of the catheter within the body.
The need for careful and precise control over the catheter is especially critical during procedures that ablate tissue within the heart. These procedures are becoming more widespread for treating cardiac rhythm disturbances.
During these procedures, a physician steers a catheter body through a main vein or artery (which is typically the femoral arterial) into the interior region of the heart that is to be treated. The physician then further manipulates a steering mechanism to place the electrode carried on the distal end of the catheter body into direct contact with the tissue that is to be ablated. The physician transmits radio frequency energy from the electrode tip to ablate the tissue and form a lesion.
Catheters for cardiac ablation and similar procedures involving inter-vascular access require a catheter body with requisite flexibility yet stiffness to maneuver through sometimes tortuous vascular paths. At the same time, these catheters require a distal end with the requisite flexibility without stiffness to be accurately steered into contact with a local tissue region. These two requirements, one for stiffness over flexibility to meet a first important set of criteria, and another for flexibility over stiffness to meet a second, equally important set of criteria, create a transition region in the catheter where the relatively stiff catheter body joins the less stiff and more flexible catheter distal end.